Answer:
391.67Hz
Step-by-step explanation:
The fundamental frequency formula in string is expressed as;
Fo = V/2L
V is the velocity of the wave = 329m/s
L is the length of the string = 42cm = 0.42m
Substitute
Fo = 329/2(0.42)
Fo = 329/0.84
Fo = 391.67Hertz
Hence the fundamental frequency of a mandolin string is 391.67Hz